Commentary Purg XXVI 43-48

The hypothetical nature of this simile is underlined by Dante's use of the subjunctive mood for its main verb (volasser).  Cranes do not and would not migrate simultaneously in two different directions, north to the Riphaean mountains and also south to the sands of the (Libyan?) desert.  Dante has developed the passage on the model, perhaps, of some of Lucan's similes concerning cranes (see C.Purg.XXIV.64-74), but the resemblance does not seem more than casual (if the closest would seem to be that found at Phars. VII.832-834).  For a meditation upon Dante's cranes here and in [Inf V 46-49] and [Purg XXIV 64-69] see Gorni (Gorn.1994.1), pp. 23-30.

      The 'former song' of the penitents is the hymn Summae Deus clementiae punctuated by the words of Mary at the Annunciation and those regarding Diana's chaste anger at Callisto ([Purg XXV 121-132]).  Each sub-group also then sends up 'the cry that most befits' it, that is, either 'Sodom and Gomorrah' or 'Pasiphaë.'